Update rails requirement from ~> 3.0.0 to ~> 6.0.3

[dependabot-preview]

Updates the requirements on rails to permit the latest version.

Release notes

Sourced from rails's releases.

6.0.3

Active Support

• Array#to_sentence no longer returns a frozen string.

  Before:

  ['one', 'two'].to_sentence.frozen?
  # => true
  

  After:

  ['one', 'two'].to_sentence.frozen?
  # => false
  

  Nicolas Dular

• Update ActiveSupport::Messages::Metadata#fresh? to work for cookies with expiry set when ActiveSupport.parse_json_times = true.

  Christian Gregg

Active Model

• No changes.

Active Record

• Recommend applications don't use the database kwarg in connected_to

  The database kwarg in connected_to was meant to be used for one-off scripts but is often used in requests. This is really dangerous because it re-establishes a connection every time. It's deprecated in 6.1 and will be removed in 6.2 without replacement. This change soft deprecates it in 6.0 by removing documentation.

  Eileen M. Uchitelle

• Fix support for PostgreSQL 11+ partitioned indexes.

  Sebastián Palma

• Add support for beginless ranges, introduced in Ruby 2.7.

  Josh Goodall

• Fix insert_all with enum values

  Fixes #38716.

... (truncated)

Commits

• b738f19 Preparing for 6.0.3 release
• 701a078 Merge pull request #39124 from eugeneius/autosave_multiple_times
• 509b9da Preparing for 6.0.3.rc1 release
• e9075d5 Add back the support to pass at as a proc in the job assertions
• 1853429 Should not rely on the global Arel::Table.engine in the framework
• c549fb4 Backports improved warning in zeitwerk:check
• 7aea213 Verify FFmpeg presence before attempting to preview videos
• 02d07cc adds missing require [Fixes #39042]
• 88c97f8 Fix autosave association bug with ActiveStorage::Attachments
• cbfbb2c Merge pull request #39014 from nimish-mehta/handle-signed-hexadecimal-literals
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
• @dependabot use these labels will set the current labels as the default for future PRs for this repo and language
• @dependabot use these reviewers will set the current reviewers as the default for future PRs for this repo and language
• @dependabot use these assignees will set the current assignees as the default for future PRs for this repo and language
• @dependabot use this milestone will set the current milestone as the default for future PRs for this repo and language
• @dependabot badge me will comment on this PR with code to add a "Dependabot enabled" badge to your readme

Additionally, you can set the following in your Dependabot dashboard:

• Update frequency (including time of day and day of week)
• Pull request limits (per update run and/or open at any time)
• Automerge options (never/patch/minor, and dev/runtime dependencies)
• Out-of-range updates (receive only lockfile updates, if desired)
• Security updates (receive only security updates, if desired)

[dependabot-preview]

Superseded by #8.